A number have orbits that take them closer into the solar system that sometimes lead them to collide with Earth or the other inner planets.
有很多小行星的轨道可以把它们带到太阳系的更内层，有时甚至会使它们与地球或其它内行星相撞。
About 20 NASA satellites are in orbits that would take them close to the debris cloud, according to the space agency.
从美国航天局获悉，约20颗美国卫星的运行轨道以后可能靠近碎片云的运行轨道。
Some take only a few years to complete their orbits.
其中一些恒星仅需几年时间就能完成一周的运行。
Orbits of this type can be positioned near collinear libration points, and for simplicity it is adequate to take linear terms into consideration in the control process.
这种类型的轨道可以离共线平动点较近，那么只需要在控制过程中考虑线性项即可，控制条件简单。
Orbits of this type can be positioned near collinear libration points, and for simplicity it is adequate to take linear terms into consideration in the control process.
这种类型的轨道可以离共线平动点较近，那么只需要在控制过程中考虑线性项即可，控制条件简单。
应用推荐